Bolt latch for auto loading firearm

ABSTRACT

An auto-loading firearm having a bolt that moves rearwardly from its forward closed position to its rearward open position and then forwardly to its closed position when the firearm is fired is provided with means for holding the bolt at its open position when the magazine is empty and the last cartridge has been fired. The bolt lock means comprises a bolt lock lever pivotally mounted on the side of the receiver, said bolt lock lever having a magazine follower engaging arm at the forward end thereof and a bolt stop arm at the rearward end thereof, said forward and rearward ends of the bolt lock lever being vertically movable between upper and lower positions when the bolt latch lever is rotated about the pivot thereof. A bolt stop lug is disposed at the rearward end of the bolt in position to be clear of the bolt stop arm when the rearward end of the bolt lock lever is at its upper position and in position to be blocked by the bolt stop arm when the rearward end of the bolt lock lever is at its lower position. A bolt lock activating surface is disposed on the upper end of the spring-pressed magazine follower of the magazine in position to contact the magazine follower engaging arm of the bolt lock lever, said bolt lock lever activating surface moving the forward end of the pivoted bolt lock lever to its upper position and moving the rearward end of the pivoted bolt lock lever to its lower position when the magazine is empty.

Unite States Patent Ruger et a1.

[451 Nov. 12, 1974 BOLT LATCH FOR AUTO LOADING FIREARM [75] Inventors:William B. Ruger, Southport; Harry H. Sefried II (New Haven, both ofConn.

[73] Assignee: Strum, Ruger & Co., Inc.,

Southport, Conn.

[22] Filed: Aug. 20, 1973 [21] Appl. No.: 389,710

[52] US. Cl. 42/16, 89/138 [51] llnt. Cl F41c 11/00, F41d 1/00 [58]Field of Search 42/16; 89/138 [56] References Cited UNITED STATESPATENTS 981,210 l/l91l Menteyne et al. 89/138 1,533,966 4/1925 Browning89/138 2,325,395 7/1943 Hammond 89/138 2,548,622 4/1951 Sampson et al89/138 2,571,132 10/1951 Harvey 89/138 [5 7] ABSTRACT An auto-loadingfirearm having a bolt that moves rear- 74 I G8 I l wardly from itsforward closed position to its rearward open position and then forwardlyto its closed position when the firearm is fired is provided with meansfor holding the bolt at its open position when the magazine is empty andthe last cartridge has been fired. The bolt lock means comprises a boltlock lever pivotally mounted on the side of the receiver, said bolt locklever having a magazine follower engaging arm at the forward end thereofand a bolt stop arm at the rearward end thereof, said forward andrearward ends of the bolt lock lever being vertically movable betweenupper and lower positions when the bolt latch lever is rotated about thepivot thereof. A bolt stop lug is disposed at the rearward end of thebolt in position to be clear of the bolt stop arm when the rearward endof the bolt lock lever is at its upper position and in position to beblocked by the bolt stop arm when the rearward end of the bolt locklever is at its lower position. A bolt lock activating surface isdisposed on the upper end of the spring-pressed magazine follower of themagazine in position to contact the magazine follower engaging arm ofthe bolt lock lever, said bolt lock lever activating surface moving theforward end of the pivoted bolt lock lever to its upper position andmoving the rearward end of the pivoted bolt lock lever to its lowerposition when the magazine is empty.

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BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to auto-loading firearms, and in particular to gas-operatedauto-loading rifles.

2. Prior Art Auto-loading firearms of the type to which the presentinvention relates have a receiver, a barrel mounted on the forward endof the receiver, a bolt slidably mounted for longitudinal travel in thereceiver behind the barrel, an auto-loading mechanism (usually,gasoperated) connected to the bolt for moving the bolt from its forwardclosed position to its rearward open position and return when thefirearm is fired, a trigger and related parts of the firing mechanism,and a cartridge magazine disposed in the receiver beneath the bolt. Whenthe firearm is fired, the bolt is caused by the auto-loading mechanismto travel from its closed position to its open position and to return toits closed position, the bolt extracting and ejecting the spentcartridge case as it travels rearwardly to its open position and thenpicking up a fresh cartridge from the magazine and inserting thecartridge in the chamber of the barrel as it returns to its closedposition.

Typically, the magazine comprises a box-like structure that is adaptedto contain a plurality of cartridges and to feed the cartridges to theloading mechanism of the firearm. The magazine is provided with avertically movable spring-pressed magazine follower that moves thecartridges upwardly toward the open upper end of the magazine where thecartridges are loaded, one at a time, into the barrel of the firearm. Asnoted, the bolt moves from its normally closed position to its openposition and then back to its closed position each time the firearm isfired. After the last cartridge from the magazine has been fired andextracted and the magazine is empty, the bolt would normally return toits closed position unless means are provided to automatically lock thebolt in its open position when the magazine is empty. When the bolt isautomatically locked in its open position, the shooter is made aware ofthe fact that the magazine is empty and reloading of the empty magazineis greatly facilitated.

Various mechanisms have heretofore been proposed for locking the bolt inits open position when the magazine is empty and the last cartridgetherefrom has been fired, extracted and ejected. Many of thesemechanisms are unduly complicated or are unreliable or subject tostructural failure. After an intensive investigation of the limitationsand problems associated with the design of a satisfactory bolt lockarrangement for semiautomatic firearms, we have now devised a new boltlock for such firearms which is sturdy, reliable and simple inoperation.

SUMMARY OF THE INVENTION As previously mentioned, firearms to which thepres ent invention relates have a receiver, a barrel, a bolt mounted inthe receiver behind the barrel, an autoloading mechanism connected tothe bolt for moving the bolt from its forward closed position to itsrearward open position and return when the firearm is fired, a cartridgemagazine disposed beneath the bolt and bolt lock means for locking thebolt in its open position when the magazine is empty and the lastcartridge from the magazine has been fired. The magazine is adapted tocontain a plurality of cartridges and has a springpressed verticallymovable magazine follower that moves the cartridges contained in themagazine upwardly into position to be loaded into the chamber of thebarrel.

The improved bolt lock means of the invention comprises a longitudinallydisposed bolt lock lever pivotally mounted on the side of the receiver,the bolt lock lever having a magazine follower engaging arm at theforward end thereof and a bolt stop arm at the rearward end thereof. Theforward and rearward ends of the bolt lock lever are each movablevertically between predetermined upper and lower positions when the boltlock lever is rotated about the pivot thereof. A bolt lock lever springurges the forward end of the pivoted bolt lock lever to its lowerposition and the rearward end of said bolt lock lever to its upperposition. A bolt stop lug is disposed at the rearward end of the bolt inposition to be clear of the bolt stop arm of the bolt lock lever whenthe rearward end of the lever is at its upper position and in positionto be blocked by the bolt stop arm of the bolt lock lever when therearward end of the lever is at its lower position. A bolt lockactivating surface is disposed on the upper end of the spring-pressedmagazine follower in position to contact the magazine follower engagingarm of the bolt lock lever when the magazine is empty, said bolt lockactivating surface moving the forward end of the pivoted bolt lock leverto its upper position and moving the rearward end of the lever to itslower position when the magazine is empty.

BRIEF DESCRIPTION OF THE DRAWINGS The bolt lock arrangement forsemi-automatic firearms of the invention will be better understood fromthe following description thereof in conjunction with the accompanyingdrawings of which:

FIG. 1 is a fragmentary side elevation of an autoloading rifle embodyingthe invention,

FIG. 2 is a sectional view along the vertical plane intersecting thelongitudinal center line of the receiver portion and the adjacent stockand forearm portions of the rifle of FIG. 1,

FIG. 3 is a fragmentary side elevation of the left side of the rifle ofFIG. 1 showing the bolt lock lever in its unlocked position,

FIG. 4 is a sectional view along line 4,7 4,7 of FIG. 3 showing the boltin its rearward position and the bolt lock lever in its unlockedposition,

FIG. 5 is a sectional view along line 5, 8 5, 8 of FIG. 3 showing thebolt in its rearward position and the bolt lock lever in its unlockedposition,

FIG. 6 is a fragmentary perspective view showing the bolt in itsrearward position and the bolt lock lever in its bolt locked position,

FIG. 7 is a sectional view along line 4, 7 4, 7 of FIG. 3 showing thebolt lock lever in its bolt lock position,

FIG. 8 is a sectional view along line 5, 8 5, 8 of FIG. 3 showing thebolt lock lever in its bolt lock position,

FIG. 9 is a sectional view along line 9 9 of FIG. 3 showing the bolt inrearward position and the bolt lock lever in the bolt locked position,

FIG. 10 is a perspective view showing the bolt lock assembly mounted onthe side of the receiver, and

FIG. 11 is an exploded perspective view corresponding to FIG. 10.

DETAILED DESCRIPTION As shown best in FIG. 1, the principal externallyvisible components of a typical gas-operated auto-loading rifle of thetype to which the present invention relates include a barrel 10, areceiver 11 to which the barrel is secured, a longitudinally movablebolt 12 mounted in the receiver 11 behind the barrel 10, alongitudinally movable slide 13 having a slide cocking handle 14 that isconnected to the bolt 12, a trigger l and trigger guard 16, a magazinelatch 17, a stock 18 having a stock forearm 19, a forearm upperhandguard 20, a gas block 21 having a block clamp portion 22, a rear sight23, and a safety activating lever 24. As shown in FIG. 2, the stock 18is formed with a vertical slot or cut-out portion 25 in which the firingmechanism associated with the trigger 16 and the magazine associatedwith the magazine latch 17 are received, and the stock forearm 19 isformed with a channel-shaped recess 26 in which the forward end of theslide 13 and the parts associated therewith are received.

Referring again to FIG. 2, the barrel is formed with a bore 28 having acartridge chamber 29 at the rearward end thereof. The longitudinallymovable bolt 12 is provided with a firing pin 30 in position to strike acartridge received in the chamber 29, an extractor 31 (shown best inFIGS. 4, 7 and 9), and a spring loaded ejector 32. The trigger ispivotally mounted on a pivot pin 34, the trigger being provided with asear arm and sear 35 and with a trigger spring 36. Secondary sear 37 isalso mounted on the pivot pin 34, the secondary sear being provided witha secondary sear spring 38. A hammer 40 is pivotally mounted on a pivotpin 41 in position to strike the rearward end of the firing pin 30 whenthe bolt 12 is in its closed position. The hammer 40 is provided with arearwardly extending sear notch arm having a primary sear notch 43 and asecondary sear notch 44. A hammer strut and spring 46 presses the hammer40 toward its firing position as shown in FIG. 2.

A magazine 48 adapted to contain a plurality of cartridges 49 is locatedin the slot of the stock 18 directly below the bolt 12 when the bolt isin its closed position. The magazine 48 advantageously comprises abox-like structure that is removable from the slot 25, the magazinebeing held in position in the slot by the front magazine latch 50 andthe manually operated rear magazine latch 17. A magazine follower 51 isdisposed within the magazine 48 below the cartridge 49, the magazinefollower having a follower spring 52 (shown best in FIGS. 4 and 7) thatpresses the magazine follower upwardly, thereby moving the cartridge 49into position to be loaded into the chamber 29 by the bolt 12.

As noted, the auto-loading mechanism is preferably gas operated,although other types of mechanisms are well known in the art, the actionshown in the drawings being a modification of the bolt and auto-loadingmechanism of the M-14 rifle. In this modification a slide block (notshown) is located within the channelshaped recess 26 of the forearm 19,the slide block being connected to the slide 13 and being held in itsforward position by the slide spring 54 that is mounted on the slidespring guide rod 55. When the rifle is fired, powder combustion gasesdrive the slide block rearwardly against the pressure of the slidespring 54 thereby causing the bolt 12 to move rearwardly to its openposition, the slide spring 54 then moving the bolt 12 forwardly to itsclosed position in a manner well known in the art.

The firing and auto-loading operations proceed as follows: The rifle isin its cocked and ready to fire condition when the hammer 40 is rotatedrearwardly against the pressure of the hammer strut and spring 46 sothat the sear notch 43 is engaged and held by the sear 35, the bolt 12is in its closed position, and a live cartridge is in the chamber 29.When the trigger 15 is pulled, the sear notch 43 is disengaged from thesear 35 thereby allowing the hammer 40 to spring forward against therearward end of the firing pin 30 which, in turn, strikes and fires thecartridge in the chamber 29. Powder combustion gases force the slide 13rearwardly against the pressure of the slide spring 54. Rearwardmovement of the slide 13 causes the bolt 12 to move from its forwardclosed position to its rearward open position. Rearward movement of thebolt 12 extracts and ejects the spent cartridge case and also rotatesthe hammer 40 rearwardly so that the secondary sear notch 44 is engagedand held by the secondary sear 37. The pressure of the slide spring 54then causes the slide 13 to move forward carrying with it the bolt 12.As the bolt 12 moves from its open position to its closed position itpicks up a fresh cartridge 49 from the magazine 48 and inserts thecartridge in the chamber 29 in the manner known in the art. When thetrigger 15 is released and allowed to return to its usual position, thesear notch 43 is engaged and held by the sear 35 while, at the sametime, the secondary sear notch 44 is released by the secondary sear 37.The rifle is now again in its cocked and ready-to-fire condition. Thissequence of operations is repeated until the magazine 48 is empty andthe last cartridge 49 has been fired.

As previously noted, it is important to provide means for retaining thebolt 12 in its open position when the magazine 48 is empty and the lastcartridge is fired. As shown best in FIGS. 3 through 11, the bolt lockmeans of the invention comprises a longitudinally disposed bolt locklever 57 pivotally mounted on the generally horizontally disposed pivotstud 58 that projects from the side wall of the receiver 11. The boltlock lever 57 is provided with a magazine follower engaging arm 60 thatextends laterally inwardly from the forward end of the bolt lock lever,and it is also provided with a bolt stop arm 62 that extends laterallyinwardly from the rearward end of the bolt lock lever 57. In theembodiment shown in the drawing the bolt lock lever 57 is mounted on theoutside of the side wall of the receiver 11, the side wall of thereceiver being formed with a forward arm opening 64 through which themagazine follower engaging arm 60 extends and with a rear arm opening 65through which the bolt stop arm 62 extends. In another embodiment of theinvention the bolt lock lever 57 may be mounted within a housing (notshown) that either forms an integral part of the side wall of thereceiver 11 or is secured to the side wall of the receiver.

As shown best in FIGS. 9, l0 and 11, the bolt lock lever 57 is held inplace on the pivot stud 58 by the retainer plate 67, the retainer plate67 being received in the slots 68 and 69 and being held in place thereinby the retainer plate plunger 70 and plunger spring 71. As noted, thebolt lock lever 57 is pivotally mounted on the pivot stud 58 so that themagazine follower engaging arm 60 at the forward end of the lever 57 andthe bolt stop arm 62 at the rearward end of the lever 57 are movablebetween predetermined upper and lower positions as hereinafter morefully explained. A bolt lock plunger 72 and bolt lock plunger spring 73are mounted in a bore 74 formed in the receiver 11, the bolt lockplunger and spring urging the forward end of the bolt lock lever 57 toits lower position and the rearward end of the bolt lock lever to itsupper position as shown best in FIG. 3.

The magazine follower 51 of the magazine 48 is provided with anupstanding bolt lock activating surface 76 that is positioned directlybelow the inner end of the magazine follower engaging arm 60 of the boltlock lever 57. The spring-pressed magazine follower 51 is disposed inthe magazine 48 below any cartridge or cartridges 49 that may becontained in the magazine. As long as there is at least one cartridge 49remaining in the magazine 48 the bolt lock activating surface 76 ismaintained out of contact with the magazine follower engaging arm 60 ofthe bolt lock lever 57 as shown in FIG. 4. When the last cartridge 49has been removed from the magazine 48 and the magazine is empty, thebolt lock activating surface 76 of the magazine follower 51 contacts themagazine follower engaging arm 60 of the bolt lock lever 57 and movesthe forward end of the bolt lock lever to its upper position as shown inFIGS. 6 and 7. That is to say, when the magazine 48 is empty and thebolt lock activating surface 76 contacts the magazine follower engagingarm 60 the upward force of the magazine follower spring 52 overcomes thedownward pressure of the bolt lock plunger spring 73 and causes theforward end of the bolt lock lever 57 to move upwardly as described.

When the magazine follower engaging arm 60 at the forward end of thebolt lock lever 57 is at its lowest position as shown in FIG. 4, thebolt stop arm 62 at the rearward end of the lever 57 is at its upperposition as shown in FIG. 5. When the magazine follower engaging arm 60is at its upper position as shown in FIG. 7, the bolt stop arm 62 is atits lower position as shown in FIG. 8.

As noted, the bolt 12 normally travels from its forward closed positionto its rearward open position and then back to its closed position whenthe rifle is fired. In the embodiment shown in the drawings, therearward end of the bolt 12 is provided with a bolt stop lug 78 inposition to clear (that is, to move freely beneath) the bolt stop arm 62of the bolt lock lever 57 when the rearward end of the bolt lock leveris at its upper position as shown in FIG. 5. However, the bolt stop lug78 of the bolt 12 does not clear (that is, it is blocked by) the boltstop arm 62 of the bolt lock lever 57 when the rearward end of the leveris at its lower position as shown in FIG. 8.

The bolt stop arm 62 of the bolt lock lever 57 is formed with arearwardly facing surface 80 that is contacted by a matching forwardlyfacing surface 79 of the bolt stop lug 78 of the bolt 12 when the boltis at its rearward position and the rearward end of the bolt lock lever57 is at its lower position as shown best in FIG. 8. The rearward facingsurface 80 of the bolt stop arm 62 is slanted slightly rearwardly andthe forward facing surface 79 of the bolt stop lug 78 is slantedslightly forwardly so that the forward facing surface 79 of the boltstop lug 78 slightly overlies the rearward facing surface of the boltstop arm 62 so as to detain the rearward end of the bolt lock lever 57at its lower position. This permits the empty magazine 48 to be removedand replaced by a loaded magazine without releasing the bolt lock andthereby allowing the bolt 12 to move forwardly to its closed position.After the loaded magazine is latched in place, the bolt lock is releasedby pulling on the slide handle 14 which disengages the bolt stop arm 62and the bolt stop lug 78, thus allowing the lever 57 to return to itsnormal unlock position.

I claim:

I. In an auto-loading firearm having a receiver, a barrel having achamber secured to the receiver, a bolt mounted for longitudinal travelin the receiver behind the barrel, an auto-loading mechanism connectedto the bolt for moving the bolt from a forward closed position to arearward open position and return when the firearm is fired, a magazinedisposed beneath the bolt, said magazine being adapted to contain aplurality of cartridges and having a spring-pressed vertically movablemagazine follower that moves the cartridges contained in the magazineupwardly into position to be loaded into the chamber of the barrel, andbolt lock means for locking the bolt in its open position when themagazine is empty and the last cartridge from the magazine has beenfired, the improvement in bolt lock means which comprises:

a longitudinally extending bolt lock lever pivotally mounted on thereceiver, said bolt lock lever having a magazine follower engaging armat the forward end thereof and having a bolt stop arm at the rearwardend thereof, said forward and rearward ends of said bolt lock lever eachbeing vertically movable between predetermined upper and lower positionswhen the bolt lock lever is rotated about the pivot thereof,

a bolt lock lever spring that urges the forward end of the pivoted boltlock lever to its lower position and the rearward end of said bolt locklever to its upper position,

a bolt stop lug disposed at the rearward end of the bolt in position tobe clear of the bolt stop arm of the bolt lock lever when the rearwardend of the bolt lock lever is at its upper position and in position tobe blocked by the bolt stop arm of the bolt lock lever when the rearwardend of the bolt lock lever is at its lower position, and

a bolt lock activating surface disposed on the upper end of thespring-pressed magazine follower in position to contact the magazinefollower engaging arm of the bolt lock lever when the magazine is empty,said bolt lock activating surface moving the forward end of the pivotedbolt lock lever to its upper position and moving the rearward end of thepivoted bolt lock lever to its lower position when said magazine isempty.

2. The firearm according to claim 1 in which the bolt lock lever ispivotally mounted on the side of the receiver for rotation about agenerally horizontal axis.

3. The firearm according to claim 1 in which the magazine followerengaging arm extends laterally from the forward end of the bolt locklever and the bolt stop arm extends laterally from the rearward end ofthe bolt lock lever.

4. The firearm according to claim 1 in which the bolt lock lever ispivotally mounted on the outside of a side wall of the receiver, inwhich the magazine follower engaging arm extends laterally inwardlythrough an opening formed in said side wall above the bolt activatingsurface of the magazine follower, and in which the bolt stop arm extendslaterally inwardly through an opening formed in said side wall adjacentthe bolt stop lug of the bolt when the bolt is at its rearward position.

. 5. The firearm according to claim 1 in which the bolt stop arm of thebolt lock lever is formed with a rearwardly facing surface that iscontacted by a matching forwardly facing surface of the bolt stop lug ofthe bolt when the bolt is at its rearward position and the rearward endof the bolt lock lever is at its lower position.

the bolt lock lever at its lower position.

1. In an auto-loading firearm having a receiver, a barrel having achamber secured to the receiver, a bolt mounted for longitudinal travelin the receiver behind the barrel, an autoloading mechanism connected tothe bolt for moving the bolt from a forward closed position to arearward open position and return when the firearm is fired, a magazinedisposed beneath the bolt, said magazine being adapted to contain aplUrality of cartridges and having a spring-pressed vertically movablemagazine follower that moves the cartridges contained in the magazineupwardly into position to be loaded into the chamber of the barrel, andbolt lock means for locking the bolt in its open position when themagazine is empty and the last cartridge from the magazine has beenfired, the improvement in bolt lock means which comprises: alongitudinally extending bolt lock lever pivotally mounted on thereceiver, said bolt lock lever having a magazine follower engaging armat the forward end thereof and having a bolt stop arm at the rearwardend thereof, said forward and rearward ends of said bolt lock lever eachbeing vertically movable between predetermined upper and lower positionswhen the bolt lock lever is rotated about the pivot thereof, a bolt locklever spring that urges the forward end of the pivoted bolt lock leverto its lower position and the rearward end of said bolt lock lever toits upper position, a bolt stop lug disposed at the rearward end of thebolt in position to be clear of the bolt stop arm of the bolt lock leverwhen the rearward end of the bolt lock lever is at its upper positionand in position to be blocked by the bolt stop arm of the bolt locklever when the rearward end of the bolt lock lever is at its lowerposition, and a bolt lock activating surface disposed on the upper endof the spring-pressed magazine follower in position to contact themagazine follower engaging arm of the bolt lock lever when the magazineis empty, said bolt lock activating surface moving the forward end ofthe pivoted bolt lock lever to its upper position and moving therearward end of the pivoted bolt lock lever to its lower position whensaid magazine is empty.
 2. The firearm according to claim 1 in which thebolt lock lever is pivotally mounted on the side of the receiver forrotation about a generally horizontal axis.
 3. The firearm according toclaim 1 in which the magazine follower engaging arm extends laterallyfrom the forward end of the bolt lock lever and the bolt stop armextends laterally from the rearward end of the bolt lock lever.
 4. Thefirearm according to claim 1 in which the bolt lock lever is pivotallymounted on the outside of a side wall of the receiver, in which themagazine follower engaging arm extends laterally inwardly through anopening formed in said side wall above the bolt activating surface ofthe magazine follower, and in which the bolt stop arm extends laterallyinwardly through an opening formed in said side wall adjacent the boltstop lug of the bolt when the bolt is at its rearward position.
 5. Thefirearm according to claim 1 in which the bolt stop arm of the bolt locklever is formed with a rearwardly facing surface that is contacted by amatching forwardly facing surface of the bolt stop lug of the bolt whenthe bolt is at its rearward position and the rearward end of the boltlock lever is at its lower position.
 6. The firearm according to claim 5in which the rearward facing surface of the bolt stop arm is slantedslightly rearwardly and in which the forward facing surface of the boltstop lug is slanted slightly forwardly so that said forward facingsurface slightly overlies said rearward facing surface to detain therearward end of the bolt lock lever at its lower position.